Objectives: 1) Continuing studies on the turtle cerebellum: a) the glial cell junctions of the turtle cerebellum. b) AChE activity in the turtle cerebellum. c) the parallel fibers of the turtle cerebellum. d) the relation between granual cells. 2) Experimental neuroanatomical studies on the cat cerebellum: a) pattern of degeneration of P.C. dendrites following axotomy. b) on the length of the parallel fibers. c) pattern of degeneration of climbing fibers in the molecular layer. d) mode of termination of spino-cerebellar and olivo-cerebellar fibers in the cat cerebellar nuclei. 3) Studies on the development and distribution of gap junctions in the cerebellum of the chick. 4) Studies on the myelin sheaths. 5) Fine structure of the ciliary ganglion in the chick. 6) Continued studies on the aminergic innervation of the cerebellum.